Investigations will be continued on granulocyte physiology, stressing oxygen-dependent bactericidal mechanisms and their metabolic concomitants. Superoxide formation, one of several metabolic processes that are activated when granulocytes are stimulated with appropriate agents, has been shown to occur in suitably prepared subcellular granulocytes fractions. The enzyme that catalyzes O2- production will be investigated by techniques of enzymology and protein purification, as will the process by which O2- production is activated. Granulocytes are known to emit light while ingesting particles; the source of granulocyte chemiluminescence will be studied spectroscopically and biochemically. O2- production by eosinophils and abnormal neutrophils (leukemic cells, and cells from patients with inherited defects of leukocyte function) will be studied. The role of myeloperoxidase-dependent and -independent oxidative bactericidal mechanisms will be studied with granulocytes themselves and with artificial O2-generating systems, using various species of bacteria and various mutant strains within a single species.